Chronic Tic Disorder, including Tourette Syndrome, (CTD) is a relatively common and typically impairing[unreadable] neurodevelopmental disorder of childhood. CTD is associated with deficits in cogntive control, including[unreadable] working memory and response inhibition, and dysfunction of cortico-striatal circuits. Although medications[unreadable] targeting these circuits have been moderately effective in reducing CTD symptoms, Habit Reversal Training[unreadable] (HRT), a behavioral technique, has shown efficacy in providing durable symptom relief without the serious[unreadable] side effects associated with pharmacotherapy. This project aims to clarify the functional[unreadable] anatomy of key circuits subserving cognitive control in youngsters with CTD, to examine hypothesized[unreadable] mechanisms of cognitive enhancement associated with HRT, and to compare these mechanisms to those[unreadable] identified for medication treatment of ADHD. Determining the neural basis of behavioral[unreadable] interventions, such as HRT, and establishing the generalizability of these findings, has the potential to[unreadable] significantly enhance development of improved treatment strategies for CTD, including the development of[unreadable] optimal treatment regimes for individual patients. As such, the aims are highly consistent with[unreadable] the overal goals of the CIDAR. A total of 60 youngsters (aged 7-16) with a DSM-IV Chronic Tic Disorder will[unreadable] receive eight weeks of HRT using a manualized treatment protocol developed and previously tested by our[unreadable] group. Youngsters will also undergo comprehensive clinical, cognitive/EEG, and fMRI evaluation at baseline[unreadable] and post-treatment. A reduced clinical and cognitive/EEG battery will also be collected mid-treatment and[unreadable] three month follow-up (responders only) to examine course and durability of response. All participants will be initially recruited and screened by the[unreadable] Research Assessment Unit (RAU) which will also recruit a matched sample of normal controls to allow for[unreadable] baseline clinical, EEG/fMRI comparison with the CTD and Project III ADHD patient samples. The fMRI and[unreadable] EEG/Cognitive components of the study will be executed through close collaboration with the Imaging and[unreadable] Research Methods (RMC) Cores, respectively. Finally, treatment-related findings from this project will be[unreadable] systematically compared to those from Project III in order to document the potential commonality of neural[unreadable] mechanisms of treatment response across multiple disorders and treatment modalities.